/*
 * Copyright 2012 Gregor Schauer
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package at.schauer.gregor.vienna.serializer.builder.discover;

import org.springframework.core.ParameterNameDiscoverer;

import javax.inject.Named;
import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Constructor;
import java.lang.reflect.Member;
import java.lang.reflect.Method;

/**
 * @author Gregor Schauer
 */
public class NamedParameterDiscoverer extends ParameterDiscoverer {
	public NamedParameterDiscoverer(Class<?>... parameterTypes) {
		super(new JSR330ParameterNameDiscoverer(), parameterTypes);
	}

	public static class JSR330ParameterNameDiscoverer implements ParameterNameDiscoverer {
		@Override
		public String[] getParameterNames(Method method) {
			return resolveParameterNames(method, method.getParameterAnnotations(), method.getParameterTypes());
		}

		@Override
		public String[] getParameterNames(Constructor ctor) {
			return resolveParameterNames(ctor, ctor.getParameterAnnotations(), ctor.getParameterTypes());
		}

		protected <T extends AccessibleObject & Member> String[] resolveParameterNames(T element, Annotation[][] parameterAnnotations, Class<?>... parameterTypes) {
			String[] names = new String[parameterTypes.length];
			for (int i = 0; i < parameterAnnotations.length; i++) {
				Annotation[] annotations = parameterAnnotations[i];
				for (Annotation annotation : annotations) {
					if (annotation instanceof Named) {
						names[i] = ((Named) annotation).value();
						break;
					}
				}
				if (names[i] == null) {
					throw new RuntimeException();
				}
			}
			return names;
		}
	}
}
